Circuit for starting and operating gaseous discharge devices



Nov. 12, 1957 FEINBERG 2,813,228

CIRCUIT FOR STARTING AND OPERATING GASEOUS DISCHARGE DEVICES Filed May 17, 1951 FIG. 3

FIG. 5

IN V EN TOR. Albert E. Feinberg United States Patent 0 see CIRCUIT FOR STARTING AND OPERATING GASEOUS DISCHARGE DEVICES Albert E. Feinberg, Chicago, Ill., assignor to Advance Transformer Co., Chicago, 111., a corporation of IllillOIS Application May 17, 1951, Serial No. 226,820

21 Claims. (Cl. 315-138) This application is a continuation in part of my application Serial No. 135,669, filed December 29, 1949, issued as Patent No. 2,558,293, and my application Serial No. 168,219, filed June 15, 1950, and relates to circuits for gaseous discharge lamps, being a combination of those two applications.

It is one of the objects of the present invention to provide a highly efficient circuit for initiating the discharge of a plurality of gaseous discharge devices, which circuit and the apparatus required therefor will be extremely simple and economical of construction and oporation.

In connection with the above object it is pointed out that my new invention utilizes a simple three winding transformer, the general construction of which is similar to that type of transformer used in circuits for starting preheated filament fluorescentlamps. Specifically, no special cores are required, no chokes or inductances need be used in the circuit, and one relatively cheap condenser may be used. The invention lies in the connections of the circuit, the manner of forming and the proportions of the windings, as well as other factors to be pointed out which give rise to the advantages of my invention.

It is a further object of the present invention to provide a circuit for initiating the discharge of a pair of instant start gaseous discharge devices seriatum and thereafter providing good regulation for the flow of current therethrough. It is a still further object of the present invention to provide a circuit for initiating the discharge of a pair of gaseous discharge devices in which following the initiation of the discharge and during operation of the devices the devices are in effect connected in substantially a series circuit. It is a further object of the present invention to provide a circuit of the above mentioned character which may be used for initiating the discharge of a single instant start gaseous discharge device.

It is a still further object of the present invention to provide a circuit for one or more gaseous discharge devices which will utilize a simple transformer for the purpose of providing the necessary starting voltage and regulating inductance. It is a still further object of the present invention to provide a circuit for one or more gaseous discharge devices that utilize a high leakage reactance winding that facilitates the building up of the necessary ignition voltage but which afterignition is so arranged in the circuit that very little current passes therethrough, whereby the remainder of the circuitincluding the gaseous discharge device or devices constitutes in effect a series circuit substantially by-passing the high leakage reactance Winding. It is a still further object of the present invention to provide a circuit for one or more gaseous discharge devices wherein a capacity reactance is associated with a high leakage reactance winding in such a manner as to build up a voltage across the reactor during starting, which will be ofreverse re- Cir 2 lationship to the normal direction of voltage in said high leakage reactance winding, whereby the voltage will be added to other voltages of the apparatus to ignite one or more of the gaseous discharge devices.

The attainment of the above and further objects of the present invention will be apparent from the following specification taken in conjunction with the accompanying drawings forming a part thereof.

In the drawings:

Figure 1 is a schematic electrical diagram showing one circuit embodying the present invention;

Figure 2 is a side elevational view of a transformer of the circuit of Figure 1;

Figure 3 is a view similar to that of Figure 2 but showing a modified form of transformer; and

Figures 4, 5, 6, 7 and 8 are schematic electrical diagrams showing modified forms of circuits embodying the present invention.

Reference may now be had more particularly to the drawings wherein like reference numerals designate like parts throughout.

In the drawings, 10 designates generally a transformer which forms an important part of my apparatus. The same is formed of three independently formed windings 11, 12, and 13 comprising a primary (P), first secondary (S1) and second secondary (S2) respectively. All of the windings are mounted upon a central winding leg 14 which is pressed into an elongate shell 15, there being a magnetic shunt 16 and an air gap 17 between the windings 11 and 12. The shell 15 and the winding leg 14 are formed of electrical steel laminations in the usual manner, thereby providing an iron core for the transformer 10.

The windings are mounted upon the shell 15 in a manner such that the primary 11 is in the center of the shell 15, the second secondary 13 is on the left end of the shell 15 although mounted on the central winding leg 14, and the first secondary 12 is on the right end of the shell 15, separated from the winding 11 by the magnetic shunt 17, and thereby constituting the winding 12, a high leakage reactance. It is obvious that the windings 12 and 13 are both loosely coupled with the primary 11, but that the first secondary 12 is what may be termed very loosely coupled to the primary, when comparing it withthe second secondary coupling.

Although both coils 12 and 13 have high leakage reactance, it may be advisable under certain operating conditions to place a small magnetic shunt 16 and a gap 17' between coils 11 and 13 to provide additionallealc age reactance as shown in transformer 10 (Fig. 3).

The windings 11 and 12, namely the primary P and the first secondary S1 are Wound in the same direction to provide additive voltage, While the winding 13 comprising the second secondary S2 is wound in an opposite direction to provide bucking voltage.

Referring to Fig. 1, note that the windings 11, 12, and 13 are connected in series providing junctures 2t and 21 therebetween, the right hand end of thetransformer 10 being designated 22 and comprising the free end of the winding 13 while the left hand end of the transformer being designated 23 and comprising the connecting lead 28 to juncture 23. Thus, it will appear that the first lamp 24 is connected across the primary and first secondary of the transformer 10, and in series with the condenser 26. The second fluorescent lamp has its right hand end connected by the lead 29 to the terminal 22, and its left hand end by lead to the juncture 20. Thus it will be obvious that the second lamp is connected across the first and second secondaries. The very loosely coupled secondary 12 is common to the circuits of both lamps 24 and 25. The usual A. C. line 31 is connected across the primary 11 to provide the necessary power.

The first secondary winding 12 has sufficient turns so that it steps up the line voltage of the primary 11 considerably, in some instances almost four times. This voltage Es is additive to the line voltage or primary voltage E and since windings 11 and 12 are in series and across lamp 24, they add to provide igniting voltage for the lamp 24. Although the winding 13 is so constituted that it provides an induced voltage Es, of more than twice Ep, since its voltages are in opposed relationship to P and S1, the voltage across lamp 25, which is the sum of Es, and E52 will be very little prior to any current flow, and certainly less than required to ignite the lamp 25.

The voltage across condenser 26 is negligible prior to ignition of lamp 24, and hence the voltage Ep combined with E51 appears across lamp 24, lights the lamp, and causes current to commence flowing.

Current now flows in the circuit of lamp 24, and since the inductive reactance of the very loosely coupled secondary S1 is so great compared to the capacitive reactance of the condenser 26, the current of such circuit is lagging. The condenser 26 assists in shifting the phase of the voltage in the first secondary 12 by lowering the total reactance of thecircuit of lamp 24. Such effect causes a higher flow of current and a consequently greater induced voltage across S1 which, of course, aids in causing lamp 25 to ignite.

I have found that the current fiow caused by the ignition of the first lamp 24 gives rise to voltage in the winding 12 whose phase is in effect reversed relative to the phase of voltage Ep and hence is additive relative to voltage E52 of winding 13, which is the secondary S2. This voltage is of such magnitude that the combined voltage appearing across lamp 25 is sufficient to ignite the lamp and cause flow of current therethrough.

With current flowing through both lamps 24 and 25, the high inductive reactance of winding 12 serves to resist flow of current therethrough and thus the effective circuit is a series circuit with both lamps 24 and 25 which may be traced as follows: Iuncture 23, lead 28, lamp 24, lead 27 and condenser 26, juncture 21, Winding 13, terminal 22, lead 29, lamp 35, lead 30, juncture 20. The

V winding 12 is thus not an effective part of the operating circuit. The condenser 26 and inductive reactance of the apparatus may so neutralize their respective effects that the power factor of current drawn from the line leads 31 using my apparatus is almost unity. It is obvious that the lead 28 and the'left hand one of the line leads 31 may constitute a single lead and that the lead 30 and the right hand one of the line leads 31 may also constitute a single lead.

In the' event the current drawn from the line is leading, an additional gap 40 may be formed at the end of the winding leg 14 thereby increasing the leakage reactance of the apparatus while incidentally preventing saturation of the core from too greatly distorting the Wave shape.

An example of apparatus embodying my invention readily could be constructed for initiating the discharge and providing regulation for a pair of fluorescent lamps known commercially as T-12 lamps having an effective length of 48 inches and being rated at forty Watts each. Such apparatus has been successfully produced and operated. The laminations-of the shell 15 of the transformer had the dimensions of approximately two and one-eighth by five and one-quarter inches, and the stack thickness was approximately one inch. The magnetic shunt may be approximately one-half inch wide, and the gap 17 approximately .010 inch. The windows for the windings 11, 12, and 13 may be adjusted in size in accordance with the physical volume of the windings.

The primary winding 11 was formed of 540 turns of number 25 wire; the first secondary winding 12 was formed of 2360 turns of number 35 wire; and the second secondary winding 13 was formed of 1270 turns of number 27 wire. The condenser 26 had a capacity of 2.6 microfarads and a rating of 440 volts maximum voltage. This apparatus operated in a highly satisfactory manner and the lamps 24 and 25 were ignited with such speed that it almost appeared that they ignited simultaneously when the power was turned on.

With a 118 volt 60 cycle A. C. line connected across the primary 11, the voltage E5, was 405 volts, and the voltage Es, was 270 volts. Es, and Ep (the line or primary voltage) are additive because the windings 11 and 12 are formed in the same wound direction. Es on the other hand is a bucking voltage because the winding 13 is formed in the reverse manner. These voltages exist before the lamps 24 and 25 are ignited. Measurements taken across the various windings bear this out in the following manner: The voltage measured from juncture 23 to juncture 21 was found to be 520 volts; the voltage measured from juncture 20 to terminal 22 (across both secondaries 12 and 13) Was found to be 150 volts; and the total sum of voltages across the entire transformer 10 taken from juncture 23 to 22 was found to be 270 volts. Since the type of lamp in the circuit requires approximately 450 volts to ignite, obviously the first larnp 24 will ignite since it has almost 520 volts appearing across its terminals, While the second lamp 25 will not ignite because the total voltage across it is only approximately 150 volts. These measurements may be taken by removing the lamps 24 and 25 from the circuit.

Once the lamp 24 has ignited and the gas therein has broken down, current flows through that lamp, said current being limited by the reactance of the circuit including the high leakage reactance of the secondary 12.

With the lamp 24 operating, measurements can be taken of the voltages and currents in the apparatus while the lamp 25 is omitted, and such measurements are as follows: E5, is now only 210 volts and E52 appears to be 258 volts, while Ep remains at 118 volts; the voltage measured from juncture 23 to juncture 21 is now 162 volts indicating a radical change which I believe is caused by a phase shift having the effect of providing a voltage vector component additive to'the voltage across S2 the secondary winding 13, and bucking the voltage Ep across the primary P; the voltage across the lamp 25 measured from juncture point 20 to 22 is now 440 volts, or sufficient to ignite the lamp 25; the voltage across the entire transformer 10 from juncture 23 to 22 is 315 volts; the voltage at the terminals of the lamp 24 is 140 volts and that across the condenser 26 is volts; the current in the primary 11 is found to be .8 ampere and the current in the lamp 24 is found to be .120 ampere.

The above measurements are static, that is, made with only the lamp 24 operating and the lamp 25 not in the circuit. This situation will arise if the lamp 25 burns out, and it will be obvious from the values given that the apparatus is operating satisfactorily and may continue to do so, providing an important emergency feature for my apparatus.

It is probable that the initial surge of current occurring with ignition of lamp 24 will produce voltages in the first secondary 12 and the second secondary 13 whose sum will be considerably greater than 440 volts, but in any event, even the sum static voltage is sufficient to ignite lamp 25 when in place. 7 7

After lamp 5 has also become ignited, current flows in its circuit, and the condition of voltages and currents in the apparatus as determined by measurements is as follows: The primaryvoltage E1) is still 118 volts; the Voltage across St the first secondary winding 12 is 310 volts; across the second secondary S2 the voltage is 308 volts; the voltage measured from juncture 23 to juncture 21 is 415 volts; the voltage across the second lamp 25 from juncture 20 to 22 is 107 volts; the voltage measured across the entire transformer 10 from juncture 23 to 22 is 130 volts; the voltage across the lamp 24 at its terminals is 107 volts; the condenser voltage is 418 volts; the current flowing in each lamp is approximately .435 ampere; and the current in the primary 11 is found to be .580 ampere. With both lamps 24 and 25 operating the current measured in secondary S1 is only .030 ampere, which demonstrates that the high reactance of the winding 12 has the effect of forcing the entire circuit to act as a series arrangement so that the major flow of current is through the lamps 24 and 25, the winding 13, and the condenser 26. With such a circuit, the reactance occasioned by the presence of the condenser 26 is effective to counterbalance the inductive reactance of the transformer windings, so that there is very good power factor correction and the current drawn from the line 31 can be adjusted practically to be almost in phase with the line voltage.

It should be obvious that for different types of lamps the circuit constants of my apparatus can be adjusted.

In the embodiment of my invention shown in Fig. 4 the connections of the circuit have been somewhat rearranged. The leads 28 and 30 have been interchanged and the windings of the transformer have been varied in accordance with the change. Thus, the transformer 60 corresponds to the transformer 10 of Fig. l and is con-. structed in quite a similar manner. The physical appearance is the same and hence is not shown here.

Electrically, there is a primary winding 61, a first secondary winding 62, and a second secondary winding 63. The winding 62 is reverse wound relative to the other two windings 61 and 63 and of such voltage relationship considering the number of turns relative to the primary winding 61, that there is a voltage developed thereacross that is sufficient to ignite the gaseous discharge device. The windings 61, 62 and 63 are all connected in autmtransformer relationship. Thus, if the voltage required to ignite the gaseous discharge device is of the order of 450 volts, and the line voltage across the primary is 118 volts, then the number of turns of the first secondary 62 is approximately four times the number of turns on the primary 61.

In the circuit of Fig. 4 the arrangement is such that with the lamps 71 and 72 out of the circuit the open circuit voltage of the secondary 62 opposes that of the primary and of the secondary 63 and is of a value substantially equal to the sum of the voltages of the primary and the secondary 63, so that the open circuit voltage across the conductors 68-70 at the time when there is no lamp at 71 will be practically zero.

The second secondary 63 has sufficient turns that the sum of voltages across 61, 63 and the in-phase component induced in 62 after the device has ignited will be sufficient to ignite a second gaseous discharge device.

Two gaseous discharge devices, such as, for example, fluorescent lamps 71' and 72 are shown. connected by leads 73 and 74 and condenser 75 to junctures 65 and 66. Lamp 72 is connected by leads 68 and 7 across the transformer.

The apparatus operates in a manner similar to the apparatus previously described herein. When the line voltage designated V (to distinguish it from the designation Ep previously used) is impressed across the primary winding 61, a voltage V51 is induced in the first secondary winding 62 suflicient to ignite the lamp 71 and cause current to flow therein. It will be noted that since the winding 62 is wound in an opposite direction Lamp 71 is game to the winding 61, the induced voltage is also opposite in direction. The current now flowing is limited by the winding 62 and the condenser 75. Due to this high leakage reactance of the winding 62 (same being arranged relative to the core and other windings of the transformer 60 in the manner that the winding 12 is arranged relative to the transformer 10), there is a phase shift of the voltage in the winding 62, causing a reverse component of the voltage V51 to appear across 65-66. This voltage component when added to the in-phase voltage Vp across the primary 61, and V5 across the second secondary 63 is sufficient to ignite lamp 72. Thereafter current flows in effect through the lamps 71 and 72, the condenser 75, and the second secondary 63 in series. The reactance of the winding 62 is so high that it is by-passed by the current flowing through the lamps. The condenser 75 serves to increase the current flow through the lamp 731 when same has become ignited by voltage V51 and acts to correct power factor of the current drawn from the line 64. The lamp 72 will draw a leading current from the line, hence the air gap 40 may be provided in the transformer of Fig. 2 as well as in the transformer of Fig. 3 to increase the magnetizing current of the primary which, being lagging, will to some extent compensate for the capacitive nature of the current drawn. by the lamp 72. The condenser in the circuit of Figs. 1 and 4 is needed only for power factor correction and may bedispensed with. When it is dispensed with the lamp 24 is connected directly to the point 21 in Fig. l and the lamp 71 is connected directly to the point 66 in Fig. 4. Other adjustments referred to herein can be made for power factor correction. i

A successful example of my apparatus as described above in connection with Fig. 4 has been constructed and operated in connection with a pair of instant start fluorescent lamps. The physical construction of the transformer 60 was substantially the same as that of transformer 10 of the previously mentioned example. The discharge devices 71 and 72 again were T12, 40 watt, forty-eight inch lamps. The primary winding 61 had 575 turns of number 26 wire, the reverse Wound first secondary had 2900 turns of number 35 wire, the second secondary had 1420 turns of number 27 wire. With a 118 volt Vp impressed across the primary winding 61, the secondary voltages prior to ignition of the lamps were 450 volts and 275 volts for Vs and V5,, respectively. V51 was sufficient to ignite lamp 71, but the combined voltages across the terminals 69 and 67 were insufficient to ignite lamp 72. After ignition of the lamp 71, the voltage across terminals 67 and 69 was of the order of 450 volts and the lamp 72 became ignited. The lamps both operated at a voltage of about 107 volts and with a current of about .425 ampere flowing therethrough. The current in the first secondary winding 62 during operation was found to be only .035 ampere since practically all the current of the winding 63, namely .410 ampere was being by-passed through the lamp 72. The condenser 75, for this example, had a capacity of 2.3 microfarads and a rating of 440 volts. The current in the primary winding 61 was found during operation to be .610 ampere.

It will be seen that the lamps of the circuit of Fig.4 are ignited seriatim, the lamp 71 being first and thereafter being followed by the ignition of the lamp 72. It will also be obvious that the effective circuit after initiation of operation of both lamps is a series circuit which maybe traced from one side of the primary winding 61 to the other as follows: Juncture 67, lead 68, lamp 72, lead70, terminal 69, winding 63, juncture 66, lead 74, condenser 75, lamp 71, lead 73, juncture 65.

While in Figures 1 and 4 I have shown circuits of the present invention each embodying two glow discharge lamps, it is within the purview of the present invention to use either of these circuits to operate a single glow discharge lamp. 7 For instance, in the circuit of Fig. 4 the lamp 71 may be omitted, in which case the conductor 73 of Fig. 4 is connected directly to the condenser so that the condenser is across the terminal 6566. This is illustrated in Fig. 5 wherein the condenser '75 is across the terminal 6566. In operation, the application of power to the terminals 64 of Fig. 5 will result in a cir- 'culating current in the circuit of the condenser 75 and the secondary winding S giving rise to the reverse component of voltage between the terminals 65 and 66. As previously described this reverse component is now additive to the voltage of the secondary S2 and the primary (P), the total being sufiicient to cause ionization of the gas in the lamp 72 to start the flow of current therethrough. With current flowing, the high leakage reactance of the secondary S1 will oppose the flow of current therethrough forcing the bulk of the current to flow from the terminal 65 through the condenser to the terminal 66, thence through the secondary S2 and the glow discharge device 72, as previously described.

The circuit of Fig. 6 is essentially the circuit of Fig. 1 except that the lamp 24 of Fig. 1 has been omitted and the condenser 26 is connected directly across the terminals 2123. It is believed that the operation of this circuit will be apparent from the description above given of the operation of the circuits of Figs. 1, 4 and 5.

In Fig. 7 there is shown a circuit substantially that of Fig. 6 except that there has been added an iron core choke 80 to improve the wave shape of the currents supplied to the lamp 25. The power factor of the apparatus as described will be capacitive, the lamp 25 drawing a leading current, since the impedance of the condenser 26 is greater than the impedance of the secondary S2. This leading power factor could be corrected by increasing the magnetizing current in the primary (P), In certain cases this can be done by varying the number of turns and the physical constants of the apparatus. An increase of the magnetizing current in the primary can be obtained by decreasing the number of primary turns or increasing the width of the end air gap 46 in the case of the core of Fig. 3. While the core structure of Fig. 2 does not have an end air gap such as the gap 40, this may be provided if desired. Two difiiculties arise if an attempt is made to increase the primary magnetizing current by decreasing the number of primary turns or increasing the width of the air gap 40. In the case of increasing the width of the end air gap, less flux will link with the secondary S2 since such flux is being forced through other leakage and shunt paths, as is illustrated with reference to the core shown in Fig. 3. Increasing the width of the gap increases its magnetic reluctance and thereby forces more flux to go through the shunt 16. This would lower the voltage that can be induced in the secondary S2, perhaps to a point where such voltage is insufficient for the purposes required. This is one reason why, in the case where an end gap is used, it is often preferable to connect the lamp across all three windings as in Figs. 4 and 5, rather than across two windings as in Fig. 6.

The addition of the choke 80 operating below saturation introduces sufiicient inductant reactance without upsetting the characteristics of the apparatus, so that the wave shape is improved and'greater lighting efliciency is achieved. It permits reduction in the size of'the Wirein the secondary S2 since the current therein is reduced. The saving in copper in the winding 52 partially olfsets the cost of the additional choke 80. In the circuit of Fig. 6 the choke may be separate from the transformer or it may be embodied in a combined structure therewith, as shown in my application Serial No. 182,212 filed August 30, 1950 entitled, Magnetic Apparatus for Gaseous Discharge Circuits.

Still another embodiment of the present invention is illustrated in the circuit of Fig. 8. Here the condenser 26 is connected across the primary and the secondary Si, as in the circuits of Figs. 6 and 7. The lamp 25 is connected across all three of thetransformer windings. primary winding in this'case is additive relative to the The secondary S1 and not as to the secondary S2. This circuit therefore operates in a somewhat different manner from the operation of the circuits previously described.

In the circuit of Fig. 8, current is first developed in the circuit including the condenser 26 connected across the primary and the secondary S1 in step-up auto-transformer relationship. The voltage across the secondary S2 under open circuit conditions, that is, with the lamp 25 omitted and the condenser 26 open circuited, is greater than the line voltage and in bucking relationship thereto. There fore, before current commences to flow in the secondary S1 the voltage across all three coils is insufficient to ignite the lamp 25. However, after current commences to flow through the condenser and the primary and secondary S1 in step-up auto-transformer relationship the reverse phase current in the secondary S1 combines with the voltage in the secondary S2 and is sufficient to ignite the device 25, after which the device acts as a straight transformer.

In the above described apparatus, While I have referred to the use of a separate choke, I do not require such an element as a part of the invention. I believe that the use of my apparatus in connection with such a choke is an improved version of that which I consider the basic novelty. In some cases the use of a choke may give more satisfactory results, but the manner of operation and construction of the apparatus is not essentially altered by the addition.

It is also desired to point out that the two windings P and S2 are relatively closer coupled together than the Winding S1 is to either. The winding S1 must in all cases have a large leakage reactance in order to give the desired results, and hence it is preferably placed on the end of the transformer core. There is a magnetic shunt between it and the remainder of the transformer. As the number of turns of S1 increases the shunt may be made smaller in width and conceivably may be dispensed with due to the high inductance provided by a great many turns. As for the other two windings, they can physically be interchanged as to position, and may even be wound on top of one another with the addition of some means providing a lagging reactance to supply that which is eliminated by this expedient. In the circuit of Fig. 7, for example, the windings P and S2 can be wound one on top of the other, giving excellent results, and a choke supplies the lagging reactance needed for good regulation.

A few additional examples of the constants of the transformers used in connection with the circuits shown in Figs. 4, 5, 6 and 7 are given below. In each case each lamination of the transformer was of electrical steel 2.125 by 5.25 inches, the framing portion being generally inch wide all around, and the central winding leg being Ms inch wide. One construction of the transformer was as follows:

Example 1.-(Transf0rmer of Fig. '3)

Stack height 7 inch.

Primary winding P590 turns of No. 26 wire.

Secondary Winding S120O0 to 2200 turns of No. 32

wire.

Secondary winding S2930 turns of No. 28 wire.

Gap 40.016 inch Gap 17-.010 inch Shunt 16'-% inch Shunt 16% inch Capacitor 75--3 /2 mfds. 400 v. A. C. R. M. S.

On a volt A. C. line, a 48" T-l2 40 watt instant start, hot cathode fluorescent lamp was ignited and satisfactorily operated, by the use of the apparatus described above. The open circuit voltage across the lamp, measured with the lamp removed was between 400 and 450 volts. During starting the current in the winding S1 was .25 amp. After starting, the current in the winding S1 was .06 amp. The total current drawn from the line during operation was 0.75 amp.

Example 2.-( Transfrmer of Fig. 3)

Stack height-l in.

Primary winding P--610 turns of No. 26 wire.

Secondary winding S1-22l0 turns of No. 35 wire.

Secondary winding S2-820 turns of No. 27 wire.

Gap 17-.0l5 inch Shunt 16% inch Capacitor 26-2.75 mfd. 400 v. A. C. R. M. S.

Choke 80 (where used) 4: inch square E-l stack of laminations inch thick having 1000 turns of No. 29 wire.

On a 115 volt. A. C. line, a 48" T-12 40 watt instant start fluorescent lamp was ignited and satisfactorily operated. In the case a choke was not used, an end gap of approximately .015 inch was used. The open circuit voltage across the lamp was approximately 430 volts. The current in S1 during starting was .200 ampere and after starting it was .050 ampere. The total current drawn during operation was .600 ampere and the voltage across the lamp was approximately 110 volts. The current in the secondary S2 during operation was .46 ampere. During starting the current in the primary (drawn from line) was 1.1 amperes.

Although the examples which have been illustrated and described show the three windings P, S1, and S2 connected respectively in series, it will be obvious to one skilled in the art, after becoming cognizant of the teachings hereof, that the invention can be applied with substantially the same effect in case the windings are connected in a different order. Thus, for example, the primary may be connected between the two secondaries, or the secondaries as illustrated and described may be interchanged as to electrical position. By adjustments of the physical constants, the results described herein and the advantages derived from the invention can be secured.

In compliancev with the requirements of the patent statutes I have here shown and described a few preferred embodiments of my invention. It is, however, to be understood that the invention is not limited to the precise constructions here shown, the same being merely illustrative of the principles of the invention. What I consider new and desire to secure by Letters Patent is:

1. In combination, a pair of gaseous discharge devices, an alternating current supply for the devices comprising .a three-winding auto-transformer having a primary, a loosely coupledfirst secondary having one end connected with the said primary, a loosely coupled second secondary, the said first secondary having its second end connected with the second secondary and in bucking voltage relationship to the second secondary, means including a a capacitive reactor connecting one. of said' devices across the first secondary, means connecting the second of said devices across the primary and the first and second secondaries, and means for connecting said source across the second devices, and the reactance of the first secondary being very high relative to the second secondary whereby after the said devices are both operating the apparatus will'form in effect a series circuit connected across the than the primary but arranged in booking relation thereto, said primary and said first. secondary and said second secondary being connected one after the other, means 10 including a. capacity reactor connecting one of said devices across the first of the two secondaries, and means connecting the second of said devices across the two secondaries and at least a part of the primary.

3. In combination with two gaseous discharge devices, means for operatingthe devices from a source of alternating current whose voltage is substantially less than the starting voltage of either of the devices, said means including reactive means having a primary winding and first and second secondary windings loosely coupled to the primary and to one another, the coupling of the first secondary winding being substantially looser relative to the other two windings whereby to constitute same a high leakage reactance Winding, the windings being connected one after the other with the first secondary winding connected between the other two windings, and the second secondary winding being connected in bucking voltage relationship to the other two windings, a capacitive reactor having one side thereof connected to the common juncture of the secondaries, means connecting the first of said discharge devices between the second side of the capacitive reactor and the common juncture of the primary winding and the first secondary and means connecting the second of said discharge devices across the primary and both secondaries.

4. In combination, two instant start gaseous discharge devices, means for operating the same from an A. C. source of voltage insufficient to ignite either device comprising an autotransformer having a primary, a first inductively reactive portion of said transformer of high leakage and of relationship relative to the primary for having a voltage induced therein greater than that of the primary voltage, a second inductively reactive portion of said transformer of high leakage and of relationship relative to the primary for having a voltage induced therein, means for impressing the voltage of said first reactive portion across one of said devices for igniting same, means connecting the second discharge device across the primary and the two reactive portions with the voltages of the two reactive portions in opposition to one another, said first portion producing after ignition of the first device a voltage having a component in reverse relation to the voltage across the first reactive portion prior to such ignition whereby it is additive relative to the voltage of the second reactive portions, the sum of said component voltage and the voltage of the second reactive portion being sumcient to ignite the second device.

5. in combination, two gaseous discharge devices, a transformer having three windings comprising a primary, first secondary, and second secondary, means forming a series circuit including one of said devices across the first secondary, means forming a series circuit including the other of said devices across the primary and the two secondaries with the voltages of the two secondaries in bucking relationship, the first of said secondaries having relatively high inductive reactance whereby to impede flow of current therethrough after ignition of both devices. i

6. A system of the character described comprising an auto-transformer having a primary Winding, a first secondary winding and a second secondary winding, both secondaries being loosely coupled to the primary, the first secondary being connected between a terminal of the primary and a terminal of the second secondary and in bucking voltage relationship to the primary, While the second secondary is connected in additive voltage relationship to the primary, a capacitive reactor, an instant start gaseous discharge device in series with. the capacity reactor and connected across the first secondary, a sec ond instant start gaseous discharge device connected across all three of said windings, the secondaries having a turn relationship to the primary whereby the first of said devices will be ignited when power is applied to the primary causing a flow of current through said first secondary, the reactance of the circuit including the first device and the first secondary being such that the current initially flowing through the first secondary following the ignition of the first device is a lagging current, which in turn will produce a component of voltage in said first secondary in phase with the voltages of the primary and second secondary such that the sum of voltages across the three windings after ignition of said first device is sutiicient to ignite the second of said devices, the said first secondary having a relatively high leakage reactance greatly to limit the flow of operating current therethrough.

7. A system of the character described comprising an auto-transformer having a primary and two secondaries, the two secondaries being arranged in voltage bucking relationship one to the other with reference to a circuit containing both secondaries, a capacitive reactor, a gaseous discharge device in series with the reactor and connected across a part of the said auto-transformer including at least the first secondary and excluding the second secondary, a second gas discharge device connected across windings of said transformer including at least both of said secondaries, said windings and primary having a turn relationship to produce upon energization of said primary a voltage across the first device sufficient to ignite the same, but across the second device insufficient to ignite the same, said first secondary having a high leakage reactance and the circuit including the first secondary and the first device being one taking a lagging current upon initiation of the flow of current through the first device whereby after ignition of said first device there will be a phase shift in the voltage thereof providing a component additive to the second secondary to increase the voltage across said second device to a value sufficient to ignite the same.

8. In combination with a gaseous discharge device, a transformer comprising a primary winding and two sec ondary windings connected with their open circuit voltages in opposition, the open circuit voltage across the two secondaries being less than the ignition voltage of the device, means connecting the device in a circuit including at least the two secondaries in tandem with their open circuit voltages in opposition, means for causing a lagging current to flow through a circuit including one of the secondaries and excluding the other secondary, a condenser in series in said last mentioned circuit, said one secondary being loosely coupled with respect to the other windings, means providing a high leakage reactance for said one secondary, whereby upon commencement of the flow of lagging current therethrough there is induced therein a voltage component additive to that of the other secondary to bring the voltage across the device to a value sufficient to ignite said device, said one secondary having a substantially higher reactance than said other secondary, and means maintaining an operating circuit for said device, said operating circuit including said condenser.

9. In combination with a gaseous discharge device, a transformer having a primary and a secondary winding, an element of high resistance inductively arranged relative to the primary, means connecting the gaseous discharge device with said secondary and said element, said element serving to provide a voltage component additive to the voltage of the said secondary winding but only after current flows in said element, and means including a condenser connected in circuit with said element for causing said current to flow upon energization of the primary, said condenser being of a capacitive reactance less than the inductive reactance of said circuit whereby the current in said circuit is a lagging current, said element being arranged in voltage bucking relationship with said secondary prior to flow of current therethrough and said additive voltage component being produced by reason of the phase reversal therein when said current flows.

10. In combination with a gaseous discharge device, a transformer having a primary and a secondary winding, an element of high reactance inductively arranged relative to the primary, means connecting the gaseous discharge de vice across said secondary and said element in tandem, said element being in series voltage relationship with and serving to provide a voltage component additive to the voltage of the said secondary winding but only after current flows in said element, and a condenser in a circuit connected across a portion of the transformer which por tion includes said element for causing current to flow through said element, the part of said circuit which is across the transformer being of substantially zero power factor and of a capacity reactance less than the inductive reactance of the portion of the transformer across which it is connected to cause said circuit to take a lagging current, said element being arranged in voltage bucking relationship with said secondary prior to flow of current therethrough and said additive voltage component being produced by reason of the phase reversal therein when said current flows.

ll. In combination, a transformer having a primary winding and two secondary windings connected in tandem one after the other, the open circuit voltage across one secondary winding being greater than that across the other two windings and in bucking relation to both of said other windings, said one secondary being less closely coupled to the primary than is the other secondary and having a higher leakage reactance than the other secondary, an instant start gas discharge device connected in a circuit including both secondaries of the transformer, the device being connected across points on the transformer having an open circuit voltage less than the ignition volt age of the device due to the bucking effect of said one secondary, and means for inducing a voltage in said one secondary which has a component in the direction of the voltage of the other secondary to bring the combined voltage to a value sufficient to ignite the discharge device.

12. In combination, a transformer having a primary winding and two secondary windings connected one after the other, the open circuit voltage across one secondary winding being greater than that across the other two windings and in bucking relation to both of said other wind ings, said one secondary being less closely coupled to the primary than is the other secondary and having a higher leakage reactance than the other secondary, an instant start gas discharge device connected in a circuit including both secondaries of the transformer, the device being connected across points on the transformer having an open circuit voltage less than the ignition voltage of the device due to the bucking effect of said one secondary, and means for inducing a voltage in said one secondary which has a component in the direction of the voltage of the other secondary to bring the combined voltage to a value sufficient to ignite the discharge device, said last means including a condenser connected in a circuit including said one secondary and excluding the other secondary and of a capacity reactance less than the inductive reactance of the circuit in which it is connected so that current flowing through said circuit including said one secondary is lagging.

13. In combination, a transformer having a primary winding and two secondary windings connected one after the other, the open circuit voltage across one secondary winding being greater than that across the other two windings and in bucking relation to both of said other windings, said one secondary being less closely coupled to the primary than is the other secondary and having a higher leakage reactance than the other secondary, an instant start gas discharge device connected in a circuit including both secondaries of the transformer, the device being connected across points on the transformer having an open circuit voltage less than the ignition voltage of the device due to the bucking effect of said one secondary, and means for inducing a voltage in said one secondary which has a component in the direction of the voltage of the other secondary to bring the combined voltage to a value sufficient to ignite the discharge device, said last means including a condenser connected in a circuit including said one secondary and excluding the other secondary and of a capacity reactance less than the inductive reactance of the circuit in which it is connected so that current flowing through said circuit including said one secondary is lagging, said last mentioned circuit having negligible resistance outside of the transformer.

14. In combination, a transformer having a primary winding and two secondary windings, the open circuit voltage across one secondary being greater than the open circuit voltage across the other secondary and greater than the primary voltage, the windings being connected in tandem one after the other with the voltage of one of the windings in opposition to the voltage of the other two windings, a glow discharge device connected across a portion of the transformer having an open circuit voltage less than the ignition voltage of the device, said portion including both of the secondary windings, and means for inducing a voltage in said one secondary which has a component in a direction opposite to the direction of its open circuit voltage to increase the voltage across said portion of the transformer to a value sufficient to ignite said discharge device.

15. In combination, a transformer having a primary winding and two secondary windings, the open circuit voltage across one secondary being greater than the open circuit voltage across the other secondary and greater than the primary voltage, the windings being connected one after the other with the voltage of one of the windings in opposition to the voltage of the other two windings, a glow discharge device connected across a portion of the transformer having an open circuit voltage less than the ignition voltage of the device, said portion including at least both of the secondary windings, and means for inducing a voltage in said one secondary which has a component in a direction opposite to the direction of its open circuit voltage to increase the voltage across said portion of the transformer to a value suflicient to ignite said discharge device, said last means including a condenser connected in a circuit including said one secondary and excluding the other secondary and of a capacity reactance less than the inductive reactance of the circuit in which it is connected so that current flowing through said circuit including said one secondary is lagging.

16. A combination such as set forth in claim 8 wherein the means for causing a lagging current to flow in cludes an electric discharge apparatus in the circuit that includes one of the secondaries and excludes the other secondary.

17. A combination such as set forth in claim 9 wherein there is provided an electric discharge apparatus in the circuit with said element.

18. A combination as set forth in claim 11 wherein the last named means includes a discharge apparatus and includes also connections connecting said discharge apparatus in a circuit that includes said one secondary.

19. A combination as set forth in claim 12 wherein a discharge apparatus is connected in series with said condenser.

20. A combination as set forth in claim 14 wherein the last named means includes a discharge apparatus and includes also connections connecting said discharge apparatus in a circuit that includes said one secondary.

21. A combination as set forth in claim 15 wherein there is provided a discharge apparatus and connections connecting said discharge apparatus in series with said condenser.

References Cited in the file of this patent UNITED STATES PATENTS 2,025,471 Osborne Dec. 24, 1935 2,212,198 Sola Aug. 20, 1940 2,317,844 Boucher Apr. 27, 1943 2,510,209 Bridges June 6, 1950 2,541,033 Cates Feb. 13, 1951 2,558,293 Feinberg June 26, 1951 FOREIGN PATENTS 594,626 Great Britain Nov. 14, 1947 

